The Pediatric Hematology/Oncology Division at Emory University is the only patient cancer center within a radius of 180 miles. The center offers multimodal therapy to children with malignant disorders. Although this division was inactive for a period of one year, it is currently very active and caring for approximately 300 children with malignant disorders. This division is unique in that it cares for private patients at Emory University Clinic and The Henrietta Egleston Hospital for Children and for indigent patients at Grady Memorial Hospital. This division cares for children in the Atlanta area (population 1.7 million), the State of Georgia, and other neighboring states including North and South Carolina and Alabama. This center is the largest contributor to the pediatric division of POG. In collaboration with the Pediatric Oncology Group, the center offers access to new intensive therapeutic regimens and experimental agents to approximately 300 children with malignant diseases. An extensive ancillary study, both at the clinical and the preclinical level, is underway in parallel with the Pediatric Oncology Group studies in children with malignant disorders. Thus, the bone marrow culture technique for the growth of granulopoietic and erythroid progenitor cells are being used to evaluate the effects of chemotherapeutic agents on granulopoiesis and erythropoiesis in man. The same technique is being applied to investigate the cryopreservation of human bone marrow cells and tumor cells. We hope that these studies will offer new insight into the effect of chemotherapeutic agents and the management of children with malignant disorders. In addition, studies are currently underway to grow childhood tumor cells in culture (Neuroblastoma and Wilms' Tumor). Studies are also underway to investigate the effect of different chemotherapeutic agents on 3 leukemic cell lines.